fix: only validate data from POST request body

With the current data validation check, an empty POST request with valid GET parameters will cause the validation to pass later when data is fetched from POST request body, it will be null.

Author: Miguel Renaud-Nolte

src/Controllers/MagicLinkController.php

@@ -65,7 +65,7 @@ public function loginAction()
     {
         // Validate email format
         $rules = $this->getValidationRules();
-        if (! $this->validate($rules)) {
+        if (! $this->validateData($this->request->getPost(), $rules)) {
             return redirect()->route('magic-link')->with('errors', $this->validator->getErrors());
         }